



siloxanes and more particularly to lubricants for metallic bearing surfaces.

- LUBRKC New York N. Ya ior to No Application December 5, 1945,

4 Serial No. 633.0%;

8 c as This invention relates to liquid phenyl alkyl their use as Thisapplication is a continuation-in-part of my co-pending application Serial Number 432,528, filed February 26, v1942, and assigned to the assignee of the present invention. 7 j

The lubricants in common use are for the most part petroleum oils. While they have awide many applications. It would be highly desirable if liquid organo-siloxanes could be found which possess improved lubricity with respect to the lubrication of relatively moving metallic bearing surfaces under moderate or heavy loads.

The primary object of this invention is to provide such a liquid for lubricating the bearing surfaces of relatively moving metallic bodies, said liquid being characterized by high resistance to oxidation, little change of viscosity with temperature and low pour point. Other objects and advantages of the present invention will be readilyapparent from the following description and claims.

I have discovered that liquid polymeric organesiloxanes comprising at least 40 mol. per cent of g the recurring unit I 4 within their structure are greatly superior in their lubricity under heavy loads to the organo-slloxanes hitherto employed as lubricants. R is a lower alkyl radical having from one to five carbon atoms. Theremainder, it any, of the orsancf siloxane mayconsist V one or more diflerent units selected from the class consisting of where the R's are the ame or difierent organic radicals selected from the class consisting of phenyl and lower alkyl radicals. The incorporation of these units into the siloxane polymer may be efiected .by hydrolyzing suitable mixtures of the corresponding silanes, i. e., SiXi, RSiXa. RzSi& and RaSlX, where X is a hydrolyzable radical, for example, an ethoxy or a chlorine radical and dehydrating the hydrolysis products. The only requirement of uch a mixture is the presence of at least 40 mol. per cent of a silane of the formula (CBH5)R$1X2.

I prefer to use those liquid organo-siloxanes within the class specified above which are substantially or completely dehydrated and wherein an appreciable amount of the unit (CeHa). cmm's1o is present where R is either a. methyl or a phenyl radical. Such an organo-siloxane would include the following structure:

It is understood, of course, that the (CsHs)RSiO unit'i present to the extent of at least 40 mol.

per cent and also that still other structural units may be present such as (CH3) aSiO-, etc. By substantially complete dehydration is meant the presence of-less than 1 per cent by weight of hy- .droxyl groups attached to silicon. More than this amount results in a tendency of the siloxane to change in viscosity due to condensation or elimi- K nation jof water.

The plienyl sum Susana liquids of this invention are characterized by relatively slight changes in visco'lty over a wide range of temperature:

lowpcur points; high flash points; low volatility; low hydroscopiclty; little,v or no corrosion or decomposing effect upon metal or rubber; and little or no gasiflcation or solidification tendencies under the higher or lower temperature conditions encountered in various types of applications.

For a better understanding otmy invention, reference should be made to the following examples wherein are disclosed compositinons falling within the purview of the invention and methods or making them.

Example 1 Polymeric phenyl ethyl silicone having a viscosity of 60 centistokes was prepared by drop- Example 2 Polymeric phenyl methyl silicone liquids of two different viscosities were prepared as follows: Phenylmethylsilicon dichloride was hydrolyzed to yield a fluid having a viscosity of 332 centistokes. This fluid was then treated with solid sodium hydroxide in an amount corresponding to a ratio of 50 silicon atoms to one sodium atom. The temperature of the mixture was held at about 150 C. for several hours until the viscosity appeared to attain a constant value. The alkali was removed by neutralization and washing, leaving a fluid of 1100 centistokes viscosity.

Example 3 A copolymer was prepared from SiCl4 and (CsHs) (CH3) Si(OC2H5) 2 in the molar ratio of 1/3 by adding aqueous ethyl alcohol to the mixture dropwise. The product was a clear viscous liquid which withstood having air blown through it for 20 hours at 250-2'70 0. without gelation.

Example 4 A copolymer from Si(OC2H5) 4 and (can) (can) SiCl2 in the molar ratio of one to three was prepared by slowly adding dropwise to the stirred mixture approximately the required amount of water diluted with an equal volume of ethyl alcohol. The product was a liquid which did not gel even when air was blown through it at 200-250 C. for 18 hours.

, Example 5 A mixture of equi-molecular parts of C2H5SiC13 and (CeHs) (C2H5)SiCh was diluted with an equal volume of dioxane. Aqueous dioxane was added I dropwise with vigorous shaking until a perma Example 6 Two-equivalents of (can) (CI-IaiSiCl-a and on of roam) (one) 28101 were mixed and diluted with of the calculated quantity was slowly added. 011

dilution with water after completion of the intercondensation the product'was precipitated as an oil. Example 7 e To a solution of (CcHc)(CH3)S1(OC2I-Is)a and dioxane. An amount of water slightly in exce'ss (CI-Ia)zSi(OCaHs)e1in equimolar proportions 95% ethyl alcohol containing a. few drops of concentrated hydrochloric, acid was added slowly with warming to effect hydrolysis and copolymerization. Water was' then added in excess. After evaporating the solvents, a-rather viscous liquid was obtained which withstood being heated at 190 C. for 72 hours without gelling.

" Example 8 A mixture of 31.3 grams (C2H5)2S1C12 and 41 grams of (CeHs) (CzI-Is)SiC1a was hydrolyzed by dropping in 7.5 cos. of water slowly with stirring at room temperature over a period of about two hours. There was considerable cooling due to evaporation of HCl. The product which was a low viscosity liquid was washed with water to remove all traces of acid. Heating at elevated temperatures for several hours failed to increase the viscosity.

Example 9 A mixture of 29.7 grams of (CH3)zSi(OCaHs)2 and 41.0 grams of (CeHs) (C2H5)SiC12 was added dropwise over a period of 8 hours to excess water. Another 200 mol. of water was then added and the mixture was stirred about 12 hours. The copolymer and aqueous layer were separated. The copolymer was then washed once with water and was then refluxed for an hour with an equal volume-of water. After another washing at room temperature no test for acid was obtained with the wash water. The sample was dried and solvents removedzby bubbling air through the sample at room temperature. It was then heated to 150 C. for about an hour under a pressure of 15 to 18 mm. The viscosity of the product at 250 C.

Example 10 A mixture of 14.8 grams of (CI-IahSKOCaHs): and 41.0 grams of (CsHs) (CaH5)SiC12 was added dropwise over a period of six hours to 50 ml. of CzHsOH and 50 ml. of water. The mixture was stirred for an hour after the chloride had all been added with 200 ml. of water. An oily liquid and an aqueous layer formed whichwere separated. The latter was extracted with diethyl ether and the ether extract was then added to the copolymer oil. The ether solution was then washed repeatedly with water until no test was obtained for acid in the wash water. The copolymer was then dried under 15 mm. pressure by heating to C. Viscosity at 25.0 C. was 29.6 centistokes.

The superiority of the liquids of the present in ,ention as extreme pressure lubricants over at er organo-siloxanes hitherto used or considered as lubricants, was demonstrated by subjecting several liquids. to the following test. A ball bearing was arranged to slide back and forth on a metal test strip while being completelyimmersed in the oil being tested. The ball bearin was also arranged in such a manner that variable loads could be applied thereto in order to through carbon-silicon linkages, said siloxane determine the effect of increasingload. The containing at least 40' mol. per cent of the relubricating property of the oil was based upon curring structural unit corresponding to the forthe wear or weight loss of the test strip after hav- 'mula (Cal-I) RSiO where R is a lower alkyl radiing been subjected to the sliding action of the 5 cal.

ball bearing for a period of two hours. The fol- 3. The method according to claim 2 wherein lowing table tabulates the results obtained in R is a methyl radical. the case of certain liquids of the present inven 4. The method. according to claim -2 wherein tion as contrasted with other organo-siioxanes R is'an ethyl radical, as well as a conventional hydrocarbon petroleum o 5. The method of lubricating relatively moving oil. In this table the wear is expressed in 0.0001 metallic bodies which comprises maintaining beram. tween their bearing surfaces a lubricant film Metals in contact wear oi test strip 0. Fluid MW Load in grams Bearing Test strip too 'uoo aooo 4.000

Univis No. 48 61 Hard ened steeL. Bolt steel...'. 5 8 ll 9 Dimethyl silicone 100 n r o 840 740 Dieihyl silicone 60 I n -4 0.-..-. 830 440 Cyclic trimer oi phenylethyl silicon 63 r n -4. l 4 6 Cylie trimer of diethyl silicone 0 o .1 n 588 872 an 160- I n do I A liquid organosilleon oxide pol er conslstin essentially of 40 mol. er cent oi C H OHgSiO units 40 mol. cent of (CHahSiOm units, and 11 mo per cent of (HrhSiOu units. p t o per It will be observed that the liquids falling withcomprising a polymeric liquid phenyl methyl in the purview of the present invention exhibited silicone. wearing properties corresponding to that of the 6. The method of lubricating relatively movt n d hydrocarbon petr le m 011 W il h ing metallic bodies which comprises maintainin orsan -silo anes. dimethyl silicone. 'diethyl 5111- between their bearing surfaces a lubricant film cone, and diethyl silicone trimer weredefinitely comprising a polymeric liquid phenyl ethyl siliinferior to both the hydrocarbon oil and the e, phenyl a yl silo anes. 'l. The method of lubricating relatively moving I'claim: Y metallic bodies which comprises maintaining 1. The method of lubricating relatively moving between their bearing surfaces a lubricant film metallic bodies which comprises maintaining be comprising a substantially completely dehydrattween their bearing surfaces a lubricant film d liquid olymeric organo-siloxane whose orcompr lng a liquid polymeric e m 40 ganic substituents consist essentially 01 lower whose organic substituents consist essentially of alkyl and phenyl radicals attached to, silicon lower alkyl and phenyl radicals attached to silithrough carbon-silicon linkages, said siloxane con through carbon-silicon linkages, said siloxt m t l a t 40 mol. per cent of the r ane containing at least 40 mol. per cent of the ring structural ,unit corresponding to the' forrecurring structural unit corresponding to the 5 mula (CcHs)RSiO where R is a lower alkyl radiiormula (CsH5)RSlO where R. is a lower alkyl cal and said siloxane also containing structur radical. 1 units corresponding to the formula 2. The method of lubricating relat vely moving metallic bodies which comprises maintaining (0393 810m between their bearing surfaces a lubricant film where R is selected from the class consisting 01' comprising a substantially completely dehydratphenyl and methyl radicals.

ed liquid polymeric organo-siloxane whose or- 8. The method according to claim 7 wherein ganic substituents consist essentially 01 lower R and R are methyl radicals.

alkyl and phenyl radicals attached to silicon JAMES FRANKHN HiZDE. 

